Removed TABLE->sort to make it possible to have multiple active calls to

filesort and init_read_record() for the same table.
This will simplify code for WINDOW FUNCTIONS (MDEV-6115)

- Filesort_info renamed to SORT_INFO and moved to filesort.h
- filesort now returns SORT_INFO
- init_read_record() now takes a SORT_INFO parameter.
- unique declaration is moved to uniques.h
- subselect caching of buffers is now more explicit than before
- filesort_buffer is now reusable even if rec_length has changed.
- filsort_free_buffers() and free_io_cache() calls are removed
- Remove one malloc() when using get_addon_fields()

Other things:
- Added --debug-assert-on-not-freed-memory option to make it easier to
  debug some not-freed-memory issues.

1 files changed, 5 insertions, 0 deletions

diff --git a/sql/item_subselect.cc b/sql/item_subselect.cc
index f22716d3d81..87c9fa696f7 100644
--- a/sql/item_subselect.cc
+++ b/sql/item_subselect.cc
@@ -58,6 +58,8 @@ Item_subselect::Item_subselect(THD *thd_arg):
 {
   DBUG_ENTER("Item_subselect::Item_subselect");
   DBUG_PRINT("enter", ("this: 0x%lx", (ulong) this));
+  sortbuffer.str= 0;
+
 #ifndef DBUG_OFF
   exec_counter= 0;
 #endif
@@ -153,6 +155,9 @@ void Item_subselect::cleanup()
   if (engine)
     engine->cleanup();
   reset();
+  filesort_buffer.free_sort_buffer();
+  my_free(sortbuffer.str);
+
   value_assigned= 0;
   expr_cache= 0;
   forced_const= FALSE;